I'm in the process of doing 3g swap.got everything hooked up and my voltage barely reads 10v and the battery light is on but when I unhook the green/red wire the light goes of. I'm heading to the store now to pick up a multimeter to see if the alternator is putting out. Could I have something wired wrong?

 

Are you checking voltage at the battery or at the alternator. how was the drive belt tension. Also Amperage readings can be very helpful.

 

Right now I'm just looking at the voltage on the dash

 

the dvom will be a good start. Is the truck killing batteries what happens if you turn on all of the components headlights radio wipers blinkers will the truck drop idle dim the lights stall.

 

I had gone through this recently. Make sure to test the alternator to see that it is actually good, as I've had 3 fail out of the box brand new. Next check the resistance on the plugs nd wires and if that checks out good make sure you have clocked the alternator properly for your truck. And make sure that your wires aren't grounding on anything they aren't supposed to.

 

I have the alternator clocked at the 12:00 position and nothing seems to be touching. I checked the voltage while the truck was running and it showed 11.55v which means the alt isn't putting out which doesn't make sense because I've had it tested before and it was good and right before I put it on I put a brand new set of brushes. I'll have it tested again to see what happens. And as far as my wiring goes I don't see where I went wrong. It's a brand new pigtail and I soldered on my connectors. I guess I'll go back and recheck them

 

I have the alternator clocked at the 12:00 position and nothing seems to be touching. I checked the voltage while the truck was running and it showed 11.55v which means the alt isn't putting out which doesn't make sense because I've had it tested before and it was good and right before I put it on I put a brand new set of brushes. I'll have it tested again to see what happens. And as far as my wiring goes I don't see where I went wrong. It's a brand new pigtail and I soldered on my connectors. I guess I'll go back and recheck them

 

Yes having it tested again would be a good idea. Have them bench test it and also test it inside the truck. If the alt tests good then it's something in the wiring most likely. Do you have it wired like the 3g diagrams show? With white to the S terminal, yellow to B terminal, battery cable from B terminal on alt to a megafuse and then to the starter solenoid, and green/red to green red on the truck? Also check the connectors and pigtails for resistance using the voltmeter, if they come back with .07 or so then that means they're working good. Nowadays just because something is new doesn't always mean it works.

 

Update: i got it benched tested today and it tested bad.failed the light circuit test. I put the old one back on for now.

 

New alternators fail often now, particularly if they are a reman or rebuilt unit. For example I went through 4 bad reman 3Gs to find the one that was good. If you don't mind spending extra $$ get a new one from somewhere like NAPA where they carry Bosch and other decent quality brands. That would save a lot of trouble imho. After getting the new alternator go have it bench tested before you start messin with it just to be sure. If it is good then you can go continue with install. I should have done it this way with my 3G swap, it would have saved me soooo much time.

 

This alternator was something I put together. I finally got it working correctly, the reason the alternator wasnt charging because one of the wires on the brushes was broke. Changed it and now it works great.